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Biomedical subjects

M Hermann

Publications and source records attributed to M Hermann.

At least 73 records · Page 4Linked to original sources
PubMed1999

Differential kinetics of primitive hematopoietic cells assayed in vitro and in vivo during serum-free suspension culture of CD34+ blood progenitor cells.

So far, blood progenitor cells (BPC) expanded ex vivo in the absence of stromal cells have not been demonstrated to reconstitute hematopoiesis in myeloablated patients. To characterize the fate of early hematopoietic progenitor cells during ex vivo expansion in suspension culture, human CD34(+)-enriched BPC were cultured in serum-free medium in the presence of FLT3 ligand (FL), stem cell factor (SCF) and interleukin 3 (IL-3). Both CD34 surface expression levels and the percentage of CD34+ cells were continuously downregulated during the culture period. We observed an expansion of colony-forming units granulocyte-macrophage (CFU-GM) and BFU-E beginning on day 3 of culture, reaching an approximate 2-log increase by days 5 to 7. Limiting dilution analysis of primitive in vitro clonogenic progenitors was performed through a week 6 cobblestone-area-forming cell (CAFC) assay, which has previously been shown to detect long-term bone marrow culture-initiating cells (LTC-IC). A maintenance or a slight (threefold) increase of week 6 CAFC/LTC-IC was found after one week of culture. To analyze the presence of BPC mediating in vivo engraftment, expanded CD34+ cells were transplanted into preirradiated NOD/SCID mice at various time points. Only CD34+ cells cultured for up to four days successfully engrafted murine bone marrow with human cells expressing myeloid or lymphoid progenitor phenotypes. In contrast, five- and seven-day expanded human BPC did not detectably engraft NOD/SCID mice. When FL, SCF and IL-3-supplemented cultures were performed for seven days on fibronectin-coated plastic, or when IL-3 was replaced by thrombopoietin, colony forming cells and LTC-IC reached levels similar to those of control cultures, yet no human cell engraftment was recorded in the mice. Also, culture in U-bottom microplates resulting in locally increased CD34+ cell density had no positive effect on engraftment. These results indicate that during ex vivo expansion of human CD34+ cells, CFC and LTC-IC numbers do not correlate with the potential to repopulate NOD/SCID mice. Our results suggest that ex vivo expanded BPC should be cultured for limited time periods only, in order to preserve bone-marrow-repopulating hematopoietic stem cells.

Animals↗
PubMed1999

Wegener's granulomatosis with unusual cavernous sinus and sella turcica extension.

Intracerebral extension of Wegener's granulomatosis (WG) is rare. We present a patient with oculomotor and trochlear nerve palsy with histologically proved WG. An MR examination revealed granulomatous tissue in nasal cavity, paranasal sinuses with meningeal infiltration, and uncommon penetration into cavernous sinus and sella turcica. The MR images before and during pharmacological therapy are presented.

Biopsy↗
PubMed1999

The testis-specific expression pattern of the growth hormone/placental lactogen (GH/PL) gene cluster changes with malignancy.

Growth hormone (GH) and placental lactogen (PL) gene transcription patterns in testicular germ cell tumors (GCT) and normal testicular tissue were comparatively investigated to identify GH/PL gene products associated with the development of GCT. This was done by nondiscriminative reverse transcriptase-polymerase chain reaction (RT-PCR), amplifying all major transcripts of any of the 5 GH/PL genes--GH-N(ormal), GH-V(ariant), PL-A, PL-B, PL-L(ike)--and subsequent analytical restriction enzyme analyses of 5'-end radioactively labeled cDNA. Surprisingly, all nonseminomatous GCT (NSGCT; n = 9) expressed GH-N, PL-A/B, and PL-L transcripts (9 of 9). Seminoma (n = 7) showed a distinctly unique pattern of GH-N and PL-A/B. GH-V products, which are hallmarks of the normal healthy testis, were not detected in any testicular cancer specimen (0 of 16). The fact that both seminomatous and NSGCT showed alterations in the same gene cluster indicates a pathogenetic relationship. Two choriocarcinoma cell lines of conceptus origin, BeWo and JAR, clearly differing from the male counterparts, exhibited a placental-derived pattern of PL-A/B and GH-V. Obviously, profound differences exist between conceptus and male germ cell GH/PL gene cluster transcription. In summary, the unique testicular pattern of GH/PL gene expression changes significantly and in directed ways with malignancy. Loss of GH-V gene expression in testicular GCT compared with normal testis and loss (seminoma) or mutation (NSGCT) of PLL gene products might have significance in terms of the relationship between these tumors and for testicular GCT development.

Adult↗
PubMed1999

Proliferative disorders of the aging human prostate: involvement of protein hormones and their receptors.

The majority of elderly men is affected by benign and malignant diseases of the prostate. Both proliferative disorders, i.e., benign hyperplasia of the prostate (BPH) and prostate cancer (PCa)-which has recently emerged as the most common male malignancy in industrialized countries-seem to be governed by endocrine factors such as sex steroid hormones, but auto/paracrine factors are involved as well. Age-related changes in levels and ratios of endocrine factors as androgens, estrogens, gonadotropins, and prolactin (PRL) and changes in the balance between auto/paracrine growth-stimulatory and growth-inhibitory factors such as insulin-like growth factors (IGFs), epidermal growth factor (EGF), nerve growth factor (NGF), IGF-binding proteins (IGFBPs), and transforming growth factor beta (TGFbeta) are meant to be responsible for abnormal prostatic growth. We investigated the existence of putative local regulatory circuits involving the protein hormones, human growth hormone (hGH), human placental lactogen (hPL), and hPRL, and their corresponding receptors in prostatic tissue specimens (transurethral resections of the prostate, TURP; n = 11), in the prostatic cancer cell lines PC3, Du145, LnCap, a virus-transformed BPH cell line (BPH-1), and in a normal healthy prostate by RT-PCRs and highly specific and sensitive immunofluorometric assays (IFMA). Neither hPRL nor hGH was detected at the mRNA or protein levels in prostatic tissue and cell lines, with the exception of 2 of 11 prostatic TURP-samples, which showed weak expression of the PL-A/B genes. PRL- and GH-receptors were expressed in all normal and pathological prostatic specimens. Surprisingly, PRL-receptor expression was not detectable in prostatic cancer cell lines. The trophic effects of exogenous hGH, hPL, and hPRL were investigated by cell proliferation assays (WST-I) in prostatic primary cell cultures and PCa cell lines. hGH significantly (p < 0.005) increased cell proliferation up to 138+/-3.2% (1 nM hGH), while hPL and hPRL revealed only moderate effects. Our data suggest that local auto/paracrine networks of protein hormone actions are not involved in the pathology of BPH or prostatic cancer. On the other hand, systemic pituitary-derived hGH can increase the proliferative response of BPH and PCa, acting directly on the target organ prostate, via the hGH-R. In this case, envisaged GH substitution in elderly people must be viewed at with caution because age-related declines in GH/IGF-I could act as a protective mechanism against abnormal cell growth.

Aged↗
PubMed1999

Hormone replacement in the aging male?.

The recent increase in the elderly population, current health trends, and awareness of age-related changes in the male endocrine system have led to discussions about the endocrine system being a "pacemaker" of male aging. Better prevention and treatment of "non-beneficial states of health" in aging men, such as generally decreased well-being and virility, increased visceral fat, osteopenia, atherosclerosis, and impaired cognitive function, is based on improved understanding of aging, particularly the significance of age-associated hormonal changes. Although not as dramatic as in women, men also show declining hormone serum concentrations with aging (Vermeulen and Kaufman, 1995). Because aging is associated with deleterious effects resembling the clinical signs of hypogonadism or states of subnormal hormone concentrations, the potential role of hormone supplementation in aging men paralleling hormone replacement therapy in postmenopausal women is the topic of discussion. The goal of hormone replacement would be to improve body composition and increase muscle strength and quality of life in men, thereby reducing mortality and morbidity. The findings so far support the need for long-term studies of hormonal supplementation in older males showing decreased hormone serum levels. Nevertheless, to date, such a use outside the context of a clinical trial is not justified.

Aging↗
PubMed1999

Salicylate promotes myeloperoxidase-initiated LDL oxidation: antagonization by its metabolite gentisic acid.

The oxidative modification of low density lipoprotein (LDL) may play a significant role in atherogenesis. Tyrosyl radicals generated by myeloperoxidase (MPO) can act as prooxidants of LDL oxidation. Taking into consideration, that monophenolic compounds are able to form phenoxyl radicals in presence of peroxidases, we have tested salicylate, in its ability to act as a prooxidant in the MPO system. Measurement of conjugated dienes and lipid hydroperoxides were taken as indicators of lipid oxidation. Exposure of LDL preparations to MPO in presence of salicylate revealed that the drug could act as a catalyst of lipid oxidation in LDL. The radical scavenger ascorbic acid as well as heme poisons (cyanide, azide) and catalase were inhibitory. The main metabolite of salicylic acid, gentisic acid, showed inhibitory action in the MPO system. Even when lipid oxidation was maximally stimulated by salicylate the LDL oxidation was efficaciously counteracted in presence of gentisic acid at salicylate/gentisic acid ratios that could be reached in plasma of patients receiving aspirin medication. Gentisic acid was also able to impair the tyrosyl radical catalyzed LDL peroxidation. The results suggest that salicylate could act like tyrosine via a phenoxyl radical as a catalyst of LDL oxidative modification by MPO. But the prooxidant activity of this radical species is effectively counteracted by the salicylate metabolite gentisic acid.

Arteriosclerosis↗
PubMed1999

The psychological ramifications of weight management.

It has long been believed that food restriction leads to psychological disturbances, including depression, preoccupation with food, and binge eating. However, recent studies suggest that comprehensive weight loss programs that incorporate behavioral treatment, diet change, and encouragement of physical activity in fact can improve the psychological state, including mood. A study conducted on subjects participating in the Weight Watchers program demonstrated positive psychological changes and improved quality of life. These changes may help motivate overweight people to maintain the physical activity and nutritional practices necessary to lose and maintain weight. Programs that include group support, like Weight Watchers, have been associated with psychological benefits independent of the amount of weight lost. Furthermore, dieters who regain lost weight do not appear to experience adverse psychological consequences. The development or exacerbation of bulimia has been linked by some authors to strict dieting, but more moderate weight control programs do not appear to produce disordered eating and may help reduce binge eating among overweight people. Individuals who successfully lose and maintain weight have been shown to experience improved mood, self-confidence, and quality of life. Additionally, decreasing levels of psychological and behavioral symptoms have been associated with increasing duration of weight loss maintenance. It can be concluded that quality of life and other psychological measures improve in individuals on comprehensive weight management programs.

Bulimia↗
PubMed1999

Melithiazols, new beta-methoxyacrylate inhibitors of the respiratory chain isolated from myxobacteria. Production, isolation, physico-chemical and biological properties.

New antibiotic compounds, melithiazols, were isolated from the culture broth of strains of the myxobacteria Melittangium lichenicola, Archangium gephyra, and Myxococcus stipitatus. The compounds belong to the group of beta-methoxyacrylate (MOA) inhibitors and are related to the myxothiazols. The melithiazols show high antifungal activity, but are less toxic than myxothiazol A and its methyl ester in a growth inhibition assay with mouse cell cultures. The melithiazols inhibit NADH oxidation by submitochondrial particles from beef heart. Melithiazol A blocks the electron transport within the bc1-segment (complex III) and causes a red shift in the reduced spectrum of cytochrome b.

Acrylates↗
PubMed1999

Reoperation as treatment of relapse after subtotal thyroidectomy in Graves' disease.

BACKGROUND AND METHODS: In Graves' disease radioiodine is the recommended treatment for relapses after subtotal thyroidectomy. If patients reject radioiodine, hyperthyroidism is managed with antithyroid drugs; surgery is generally not considered as an alternative. Here we retrospectively analyzed 30 consecutive patients with Graves' disease who had recurrent hyperthyroidism after subtotal thyroidectomy. RESULTS: On relapse after the first operation, the patients were initially treated by medication; 25 opted for definitive treatment (19 for reoperation and 6 for radioiodine). Operations consisted of 10 unilateral and 8 bilateral resections (total or near-total with capsular remnants of < 1 g) and 1 transsternal approach (because of dystopic intrathoracic thyroid tissue). The decision between a unilateral and a bilateral reintervention was based on the ultrasonographic determination of remnant volumes. These size estimates were valid because they were significantly correlated to the weight of the resected remnants (r = 0.92, slope = 0.95). Eighteen of the 19 patients were adequately treated by this approach. Unilateral resection was performed in 1 patient with a remaining contralateral remnant of 5.4 mL; this patient had a second relapse. The complication rate was low (2 cases of transient recurrent nerve injury and 1 of transient hypocalcemia). CONCLUSION: Provided that no contraindication is present, reoperation is safe, effective, and expeditious in recurrent hyperthyroidism. Because the likelihood of a recurrence depends on the total remnant size, the goal is to keep it below 2 g. Preoperative ultrasonography can effectively guide the decision between a unilateral and a bilateral resection.

Adult↗
PubMed1998

Coexpression of gonadotropic hormones and their corresponding FSH- and LH/CG-receptors in the human prostate.

BACKGROUND: Benign prostatic hyperplasia (BPH) affects the majority of elderly men, and prostate cancer is the most common male cancer. Prostatic growth and function are thought to be regulated by steroid hormones, primarily androgens and estrogens, but nonandrogenic hormones must also be considered. The increasing evidence of para/autocrine functions of the gonadotropic glycoprotein-hormones (GPH), their allocation to the superfamily of cystine-knot growth factors, and luteinizing hormone (LH)/chorionic gonadotropin (CG)-receptor (R) gene expression in nongonadal tissues led us to investigate intraprostatic GPH and GPH-R gene expression. METHODS AND RESULTS: RT-PCR and subsequent Southern hybridization and/or restriction enzyme analysis of BPH and prostatic adenocarcinoma demonstrated that all three human (h) gonadotropic hormones, i.e., follicle-stimulating hormone (FSH), LH, and CG, as well as the corresponding FSH-R and LH/CG-R, are transcribed intraprostatically. Significant amounts of the alpha and beta subunits of hCG were secreted by short-term primary cultures of human BPH tissues, as detected by highly sensitive and specific time-resolved immunofluorometric assays (IFMAs). CONCLUSIONS: Our data suggest that prostatic- and pituitary-derived GPH act directly on the prostatic gland, particularly FSH via the FSH-R, thereby possibly modulating locally acting key hormones and growth factors involved in BPH development.

Chorionic Gonadotropin↗
PubMed1998

Expression and conservation of apolipoprotein AIV in an avian species.

In birds, intestinally derived lipoproteins are thought to be secreted directly into the portal vein rather than to enter the circulation via the lymphatic system as in mammals. Hepatic clearance of these so-called portomicrons must be rapid, but the protein(s) mediating their catabolism, presumably analogues of the 36-kDa mammalian apolipoprotein E, have not been identified. In searching for such a mediator(s), we have isolated a hitherto unknown 38-kDa protein from chicken serum, which we identified by microsequencing and molecular cloning as a counterpart to mammalian apolipoprotein AIV (apoAIV). Mature chicken apoAIV consists of 347 amino acids, lacks cysteine residues, and displays 57% sequence identity with human apoAIV and, to a significantly lesser extent, with apoAIVs of rodents. This first nonmammalian apoAIV characterized is the smallest homologue reported so far, because of the lack of repeated motifs at the carboxyl terminus with the consensus sequence Glu-Gln-Glu/Ala-Gln, a hallmark of mammalian apoAIVs. Chicken apoAIV (isoelectric point, 4.65) is also considerably more acidic than its human counterpart. Agarose gel electrophoresis revealed that unlike human apoAIV, which migrates to a pre-alpha-position, chicken apoAIV shows fast alpha migration. Functional characterization demonstrated that the avian protein is able to activate the enzyme lecithin:cholesterol acyltransferase. Roosters and hens express apoAIV predominantly in the gut, one-fifth as much in the liver, and no other sites of expression are identifiable by Northern blot analysis. Although pronounced intestinal synthesis is common to apoAIVs, the features of the avian protein support the notion that it represents a prototype of an apoprotein that evolved to acquire possibly distinct functions in mammals and birds.

Amino Acid Sequence↗
PubMed1998

Reduced phagocytosis of apoptotic cells in malignant lymphoma.

Efficient removal of lymphocytes undergoing programmed cell death (apoptosis) by macrophages plays an important role for the proper function of normal immune system. Furthermore, in malignant lymphoma, elimination of apoptotic tumor cells by phagocytes contributes to the anti-tumor immune response. It is unknown, however, whether macrophages in normal and malignant lymphoid tissues differ in their ability to recognize and remove apoptotic cells. Our present results demonstrate that normal and malignant lymphoid tissues differ according to the extent of the infiltration by macrophages. The highest densities of macrophages (p < 0.0001) were detected in diffuse large B-cell lymphoma, centroblastic (DLBCL-CB) and immunoblastic variants and Burkitt's lymphoma. The grade of the macrophage infiltration correlated with the proliferation rates of the tumors (p < 0.0001). Compared with normal lymphoid organs, malignant lymphoma contained lower percentages of apoptotic cells phagocytosed by tissue macrophages (p < 0.001). Of all lymphomas tested, mantle cell lymphoma and DLBCL-CB expressed the lowest percentages of phagocytosed apoptotic cells (p < 0.0001).

Apoptosis↗
PubMed1998

Equinins in equine neutrophils: quantification in tracheobronchial secretions as an aid in the diagnosis of chronic pulmonary disease.

Equinins are a closely related group of proteins found in equine neutrophil granules. They demonstrate proteinase inhibiting activity restricted to microbial proteinase K and subtilisin, and they also possess antibacterial and antiviral properties. Antiproteinase K activity was measured in tracheobronchial secretions (TBS) of horses with mild (n = 15), moderate (n = 30) and severe (n = 16) chronic pulmonary disease, to determine its usefulness as an indicator of severity of disease and to measure neutrophil content. Determination of proteinase K inhibiting activity was based on a colorimetric assay measuring the suppression of 4-nitroaniline liberation from the synthetic substrate succinyl-L-alanyl-alanyl-alanin-4-nitroanilid, a process mediated by proteinase K. Proteinase K inhibiting activity proved to be a valid and simple indicator for assessing neutrophil content in TBS and a useful parameter to determine the severity of chronic pulmonary disease in the horse.

Animals↗
PubMed1998

Preventive strategies in endothelin-induced renal failure.

The endothelial vasoconstrictor endothelin (ET) can induce acute renal failure when fibrinolysis and vasodilatory prostanoids (PGs) are inhibited. This study compares therapeutic agents preventing ET-induced acute renal failure in anesthetized female pigs. We investigated the effect of four ET boli (1.5 microg/kg, i.v.) after pretreatment with indomethacin (2 mg/kg) and epsilon-aminocaproicacid (100 + 50 mg/kg) alone (controls, group 1) or during additional nifedipine (10 microg/kg/h; group 2), hirudin (0.5 mg/kg; group 3), or enalapril (2 x 0.15 mg; group 4) on coagulation, PGs, and renal function. The ET-induced blood pressure increase was lower in groups 2 to 4 (lowest in group 3, P < 0.05). PG synthesis was blocked in all groups. The initial hypercoagulability (controls) resulted in disseminated intravascular coagulation that was prevented by hirudin and was attenuated in groups 2 and 4. At the end of the experiment, creatinine clearance was significantly (P < 0.05) decreased. The recovery of renal function two hours after the last ET bolus was most pronounced in the hirudin group. All therapeutic drugs attenuated ET-induced impairment of renal function. Hirudin seems to be the most potent protective drug. Prevention of further ET release evoked by ET-mediated secretion of thrombin might explain this. These results suggest three important pathways for ET's hemodynamic and renal effects.

Acute Kidney Injury↗
PubMed1998

Reassessment of the role of human placental lactogen in physiological non-pregnant and pathological conditions.

The recent demonstration of ectopic production of human placental lactogen (PL) in the human testis and ovary prompted us to reassess its role under non-pregnant physiological and pathological conditions. Possible physiological hPL concentrations and potential age-related changes in the sera of healthy young and elderly individuals (n = 75) selected according to the SENIEUR-protocol were investigated by a highly sensitive (detection limit: 2 pg/ml) and specific (cross-reactivity with prolactin and human growth hormone (hGH) of less than 0.001% and 0.0001%, respectively) monoclonal antibody-based time-resolved fluoroimmunoassay (IFMA) established in our laboratory. All individuals, even the aged probands (mean age: 72 +/- 3a), had hPL-levels below 20 pg/ml, in contrast to glycoprotein hormones, such as luteinizing hormone or human chorionic gonadotropin (hCG). To determine the significance of hPL as a tumour marker, serum samples of 12 testicular cancer patients with highly elevated levels of holo-hCG (mean: 42.490 ng/ml) at diagnosis were followed over 6-12 months and analysed with the hPL-IFMA. Elevation of hPL was seen in 10 patients, but the respective levels were 2-3 orders of magnitude smaller than those of holo-hCG and returned earlier to undetectable values. These in vivo data were compared to the hPL secretion pattern of the choriocarcinoma cell lines JAR and BeWo in vitro. In tissue culture supernatants of the two cell lines hPL was detected only in JAR cells, whereas both cell lines secreted holo-hCG. In conclusion, the fact that hPL is not physiologically present in peripheral blood but is produced ectopically in the human testis and ovary suggest auto/paracrine functions of this molecule. The significance of hPL as a tumour marker for patients with testicular cancer is limited as it provides no additional information to holo-hCG.

Adult↗